Combustion engine oil with additive to prevent sludge formation and deterioration

ABSTRACT

A METHOD FOR PREVENTING SLUDGE FORMATION AND DETERIORATION OF A LUBRICATING OIL COMPOSITION FOR INTERNAL COMBUSTION ENGINES COMPRISING FORMULATING THE LUBRICATING OIL COMPOSITION TO CONTAIN ONE PART BY WEIGHT OF AN N-NITROSO ARYL HYDROXYL AMINE COMPOUND OR METAL SALT THEREOF PER 100-10,000 PARTS BY WEIGHT OF THE OIL AND A CONCENTRATE FOR USE IN ADDING TO CRANK CASE OILS.

United States Patent US. Cl. 252-3345 5 Claims ABSTRACT OF THE DISCLOSURE A method for preventing sludge formation and deterioration of a lubricating oil composition for internal combustion engines comprising formulating the lubricating oil composition to contain one part by weight of an N-nitroso aryl hydroxyl amine compound or metal salt thereof per 100-10,000 parts by weight of the oil and a concentrate for use in adding to crank case oils.

This invention relates to a composition for lubrication of surfaces to minimize friction and wear and it relates more particularly to a lubricating oil composition for use in internal combustion engines to prevent the formation of sludge and other gummy or polymerizate materials which make it necessary frequently to change transmission oil. It relates further to an additive in the form of a concentrate for addition to lubricating oils to prevent the formation of such sludges and the like in use.

The invention will be described with reference to a lubrieating oil composition for internal combustion engines, but it will be understood that such lubricating oil may have application to other engines and parts wherein fuel is burned for the generation of heat or vapor.

Engines which operate by the combustion of a fuel, such as fuel oil, kerosene, gasoline, natural or artificial gas, liquefied gas and the like, make use of a lubricant, such as a paraffin based lubricating oil, to ease the movement of parts. Sludges or other polymerizates generally form or otherwise collect in such lubricating oil compositions with the result that the oil tends to cause the clogging of passages or otherwise become less effective, with the requirement for frequent change. Sludges in fuel combustion engines form, at least in part, from fuel degradation prodnets of lower molecular weight. These low molecular Weight materials, which may include ethylenically unsaturated molecules which are capable of polymerization under the conditions existing in the crank case and/or engine, may undergo polymerization to form varnish or oil insoluble resinous sludge or polymerizates, in which heat and the oxides of nitrogen, which are formed during fuel combustion by nitrogen fixation of oxygen and nitrogen in the air admixed with the fuel, play a prominent part as catalyst.

Such thermal dissociation can itself produce sludge polymerizates or other tarry products which will be taken up by the lubricant, or the decomposition or organic compounds to yield lower molecular weight unsaturated or polymerizable compounds which react under the temperature conditions to form polymerizates or other higher molecular weight insoluble compounds which collect in the lubricating oil as solids or sludge.

Resin formation in an internal combustion engine causes sticking of the valves with a resulting loss in power and performance. Moving parts, such as valve lifters, pistons and the like are subject to increased friction and wear by reason of the presence of resins or sludge in the crank case oil, thereby to necessitate frequent oil change.

It is an object of this invention to produce a lubricating oil composition and concentrate which restrains the for- 3,650,952 Patented Mar. 21, 1972 mation of sludge, polymerizates, or other insoluble compounds during use as a lubricant for internal combustion engines, whereby the effective life of the lubricating oil composition is materially increased, whereby passages lubricated by the oil composition remain open, wherein a lubricant which remains cleaner and retains its lubricating properties over a longer period of time is provided, and wherein the lubricating oil composition remains stable, even at high temperature.

In accordance with the practice of this invention, the conventional lubricating oils, such as the paraffin based lubricating oils, often used for internal combustion engines, are formulated to contain, as an essential component thereof, an oil soluble N-nitroso aryl hydroxyl amine and preferably an oil soluble salt thereof, and more preferably the iron salt of -N-nitroso phenyl hydroxyl amine.

Representative of the lubricating oils are oils having a petroleum or parafiin base and preferably free of resin.

Representative of the N-nitroso aryl hydroxyl amines are -N-nitroso phenyl hydroxyl amine, N-nitroso naphthyl hydroxyl amine, N-nitroso beta ethyl phenyl hydroxyl amine, N-nitroso beta methyl phenyl hydroxyl amine, N- nitroso chlorophenyl hydroxyl amine, N-nitroso bromophenyl hydroxyl amine and the metal salts thereof, such as the salts of titanium, vanadium, tin, molybdenum and preferably the iron salts of suchv N-nitroso compounds.

It is sufiicient if the dissolved N-nitro aryl hydroxyl amine or its soluble salts is present in the lubricating oil in an amount within the range of 1 part by weight of the nitroso compound or its salts to to 10,000 parts by weight of the oil, and preferably in an amount within the range of 1 part by weight per 200 to 600 parts by weight of the oil. The nitroso compound or its soluble iron salt can be formulated in a concentrate having 10 to 100 times the concentration described above for addition to lubrieating oils having corresponding 10 to 100 fold dilution to provide a lubricating oil composition containing the N-nitroso aryl hydroxyl amine or salt in the desired concentration as described above.

The nitroso aryl hydroxyl amine or its salt can be added directly to the oil for solution but, when use is made of a corresponding salt, such as the iron salt of N-nitroso phenyl hydroxyl amine, it is preferred to dissolve the salt in a hydrocarbon solvent, such as acetone, methyl ethyl ketone, benzene, naphthalene or the like which can be blended with the oil in the desired amount. For this purpose, a solvent solution containing from 0.1% to 10% by weight of the salt of N-nitroso aryl hydroxyl amine can be used.

The following examples are given by way of illustration, but not by way of limitation, of the practice of this invention:

EXAMPLE 1 Crank case oil for gasoline burning engines:

25 grams iron salt of N-nitroso phenyl hydroxyl amine 2 gallons parafiin based resin-free lubricating oil 4 grams additive for preventing rust and corrosion EXAMPLE 2 Diesel engine oil:

25 grams iron salt of N-nitroso phenyl hydroxyl amine 1 gallon petroleum oil, parafiin based EX AMP LE 3 Crank case oil for kerosene burning jet engines:

25 grams molybdenum salt of N-nitro phenyl hydroxyl amine 4 gallons parafiin based resin-free lubricating oil EXAMPLE 4 1 part by weight of a titanium, vanadium, tin or iron salt of an N-nitroso aryl hydroxyl amine compound 10-1000 parts by weight lubricating oil plus minor additives in the form of corrosion retarders,

anti-oxidants and the like EXAMPLE 5 Concentrate for addition to crankcase oil for internal combustion engines:

100 parts by weight iron salt of N-nitroso naphthyl hydroxyl amine 150 parts by weight oil 50 parts by weight benzene In Example 5, the iron salt is first dissolved in the henzene and the solution is blended with the oil to produce a concentrate which may be added to oil in the crankcase or the like in the ratio of 1 part by weight concentrate to 50-200 parts by weight of oil.

In Examples 1 to 4, the iron salt of N-nitroso phenyl hydroxyl amine can be replaced in whole or in part with equivalent amounts of oil soluble tin, titanium, molybdenum or vanadium salts of N-nitroso aryl hydroxyl amines in which the aryl group is phenyl, naphthyl, chlorophenyl or the corresponding N-nitroso aryl hydroxyl amine. Other additives currently being employed in lubricating oil compositions can be included to secure their desired effects.

When the compositions of this invention, as represented by Examples 1 to 5, are used in the crankcase of an internal combustion engine, the formation of sticky or gummy resins or sludge is markedly reduced. The lubricating oil remains relatively free of sludge, polymerizates, or other insoluble matter and its original viscosity and lubricity is maintained over an extended period of use thereby less frequently to require an oil change. As a result, the useful life of the lubricant is materially increased with decrease in engine wear and fuel consumption.

It will be understood that changes may be made in the details of formulation without departing from the spirit 4 of the invention, especially as defined in the following claims.

I claim:

1. A lubricating oil composition for internal combustion engines comprising a lubricating oil in major amounts containing an oil soluble N-nitroso aryl hydroxyl amine or metal salt thereof selected from the group consisting of titanium, vanadium, tin, molybdenum and iron in an amount within the range of 1 part by weight of the N- nitroso compound per -10,000 parts by weight of oil.

2. A lubricating oil composition as claimed in claim 1 in which the N-nitroso compound is present in a dissolved state in an amount within the range of 1 part by weight per 200-600 parts by weight of oil.

3. A lubricating oil composition as claimed in claim 1 in which the aryl group of the N-nitroso compound is selected from the group consisting of phenyl, naphthyl, beta ethyl phenyl, beta methyl phenyl, chlorophenyl and bromophenyl.

4. A lubricating oil composition as claimed in claim 1 in which the N-nitroso aryl hydroxyl amine compound is an iron salt of N-nitroso phenyl hydroxyl amine.

5. A lubricating oil composition as claimed in claim 1 in the form of a concentrate to be added to lubricating oil in which the concentrate contains 1 part by weight of the N-nitroso aryl hydroxyl amine or salt per 1 to 100 parts by weight of oil.

References Cited UNITED STATES PATENTS 2,326,938 8/1943 Fuller et a1. 25251.5 R 2,345,580 4/1944 Buxton 252-52 FOREIGN PATENTS 846,239 8/1960 Great Britain.

DANIEL E. WYMAN, Primary Examiner W. H. CANNON, Assistant Examiner U.S. Cl. X.R. 252-491, 51.5 R 

